Find the average momentum of molecules of hydrogen gas in a container at temperature `300K`.

Explanation

To find the average momentum of molecules of hydrogen gas in a container at a temperature of 300 K, we can follow these steps:

### Step 1: Understand the concept of average momentum
The average momentum of gas molecules can be defined as the product of the mass of the molecules and their average velocity. However, due to the random motion of gas molecules, the average velocity of all the molecules in a container is zero.

### Step 2: Define the average momentum mathematically
The average momentum \( P_{avg} \) of the gas molecules can be expressed as:
\[ P_{avg} = N \cdot m \cdot V_{avg} \]
where:
- \( N \) is the number of molecules,
- \( m \) is the mass of a single molecule,
- \( V_{avg} \) is the average velocity of the molecules.

### Step 3: Analyze the average velocity
In a gas, especially at a temperature like 300 K, the molecules move in random directions. For every molecule moving in one direction, there is likely another molecule moving in the opposite direction. Therefore, the average velocity \( V_{avg} \) of the gas molecules is zero:
\[ V_{avg} = 0 \]

### Step 4: Calculate the average momentum
Substituting \( V_{avg} = 0 \) into the equation for average momentum gives:
\[ P_{avg} = N \cdot m \cdot 0 = 0 \]

### Conclusion
Thus, the average momentum of the molecules of hydrogen gas in the container at 300 K is:
\[ P_{avg} = 0 \]